Lubricants



United States Pate t LUBRICANTS No Drawing. Application November 20,1951, Serial N0. 257,410

18 Claims. (Cl. 252-48.8)

This invention relates to new and improved lubricants. In one aspectthis invention relates to improved lubricating oils containing selectedsulfun'zed compounds as addition agents. In another aspect thisinvention relates to the preparation of materials having particularlyutility as mineral lubricating oil addition agents.

At the present time it is common practice to enhance or modify certainof the properties of lubricating oils through the use of additives orimprovement agents, to render the oil serviceable over the adverseconditions encountered, when employed in internal combustion enginessuch as automotive, aircraft, and diesel engines. Our invention isconcerned with new lubricating oil addi- Iives or improvement agents,which when incorporated with a mineral oil employed as a lubricant in anengine of the internal combustion type, impart valuable improvements tothe oil, particularly as regards corrosion inhibiting properties, andincreased resistance of the oil to oxidation.

An object of this invention is to provide new lubricating oilcompositions. Another object is to provide new mineral oil additionagents. Another object is to provide for an increase in theanticorrosion and antioxidation characteristics of a mineral lubricatingoil. Another object is to provide a class of mineral lubricating oiladdition agents, which when incorporated with a mineral lubricating oilin service in an internal combustion engine of the type above described,greatly reduce, :the corrosive action of the oil on engine bearingparts, and increase its resistance to oxidation. Other objects will beapparent to those skilled in the art in the light of the accompanyingdisclosure. I

In accordance with our invention we provide as new lubricantcompositions, a mineral lubricating oil containing in solution a minorproportion of a sulfurized diarylalkane. Our invention is based on ourdiscovery that diarylalkanes can be sulfurized to form a productmaterial, which when dissolved in a mineral lubricating oil improves theresistance of the oil to oxidation and inhibits corrosive action of theoil on engine parts in contact therewith.

The sulfurized diarylalkaue addition agents of our invention are thoseproduced by sulfurization of diarylalkanes, when employing sulfurmonochloride as the sulfurizing agent either non-catalytically or in thepresence of a catalyst, as described hereafter. Diarylalkanes to besulfurized to produce our addition agents contain the two aryl groupspreferably attached to alkane carbon atoms either adjacent each other orseparated by no more than one carbon atom. The aryl groups of thediarylalkane can be the same or different and are comprised of phenyl,naphthyl, anthryl and phenanthryl radicals, substituted orunsubstituted.

The diarylalkane to be sulfurized can be produced in any desired manner.One preferred method involves the alkylation of an aromatic compoundsuch as benzene, naphthalene, anthracene, phenanthracene, or such are-2,7710% Patented Dec. 4, 1 956 2 matics substituted, as for exampletoluene, xylene, phenol, dimethyl naphthalene, diamyl naphthalene,dioctyl naphthalene, di-tert-dibutyl anthracene, di-isoamylphenanthrene,tri-tert-butyl phenanthrene, methyl-tertbutylnaphthalene, ethyldodecylbenzene, cumene, and the like, and particularly long-chain alkylaromatics, with conjugated diolefins often, containing from 4 to 6carbon atoms, as for example, 1,3-butadiene, 1,3-pentadiene,1,3-hexadiene, 2-methyl-l,3-pentadieue, and the like. Other diolefinsparticularly representative of those that can be alkylated with anaromatic to produce, the diary!- alkane to be sulfuiized include,conjugated dodecadiolefins, viz. 1,3-, 2,4-, 3,5-, 4,6- and5,7-conjuated octadienes, conjugated heptadienes, or such dienes alkylsubstituted. Such an alkylation can be etfected under any appropriatealkylating conditions and in the presence of a'suitable catalyst as, forexample, hydrogen fluoride, boron fluoride, a boron tiifluoride-watercomplex, a complex of boron trifluoride with aqueous hydrogen fluoride,aluminum chloride, and the like, the specific alkylating temperature andtime conditions being characteristic of those generally employed inconjunction with the particular ice alkylation catalyst employed.

The sulfurization of the diarylalkane is conducted, employing sulfurmonochloride as the sulfurizing agent, generally at a temperature withinthe limits of 20 and 110 C., and preferably within the narrow range ofabout 40 and 60 C. However, the rate of sulfurization reaction variesconsiderably depending on the particular substituents on the arylradical, if any and on their position. For example, thosediphenylalkanes in which the para position of the phenyl group isoccupied, sulfurize much more slowly than when the para position isfree.In such a case, i. c. When the para position is substituted, a highertemperature is generally preferred, the optimum level likely beingbetween about 60 and 110" C., so as to effect the desired sulfurizationin a reasonable length of time. However, the rate of the sulfurizationcan be increased also by etfecting the reaction in the presence of asuitable catalyst, such as zinc dust. Accordingly, if desired, we canincrease the rate of the sulfurization by increasing the sulfurizationtemperature, or by the use of a suitable catalyst, or both. If time istoo short, conversion is low; if too high, some of the desired oilsoluble product is converted into insoluble material. The optimumreaction time will depend on other reaction vari: ables such as the molratio of sulfur monochloride to the diarylalkane, presence and characterof a catalyst, temperature and the like. The optimum timeff may bedetermined by routine test. For the sulfuriz'ation condi tionsillustrated in the examples, a sulfurization time of from 30 to minutesispreferable.

The addition agent of our inventionappears to be formed by coupling ofsulfurized monomers and non-sulfurized monomers (the selecteddiarylalkane) together with sulfur to form the resultingsulfur-containing polymer. In carrying out the sulfurization it isimportant to effect the careful control of the sulfurization conditions'to form highest yields of oil-soluble sulfur containing product.Accordingly it is important to effect the sulfurization within thereaction time above described, 'by carefully selecting the requisitetemperature level, and

if needed, a suitable catalyst, as well as to employ' a' ;S 5. I$etest?! .9 ha.. .!in latt sa iaaatqnetties, and of suitable gradeajndviscosity can be employed in compounding our impfdved lubricating oilcomposiip rzeariit etst qd hasetnzate alset negal, .having ayiscqsityat.F as-1owas45 Q h seii i p the composibje te df All oughthelcoiicentration of ed ll' not gen r -i11y',ex eea l0 ons jcanbejemploye'd, i'f de- :Ex mp j- 1Xylene, in troducedinto an alkylationzone with 1,3- but adieriejna'mol ratio to maqienejor approximately 2 1'631.7 pounds of total-reactants was 'alkylat'ed with the butadi'e ne atatmosphericpressure and atateinperaire-c560 to=70 FLiiii the'prese'nceofaBF3 HF H2O catalyst to form dixylylbutane. Thecatalyst was-prepared bysaturating 47 percent aqueous HF with BFs. The catalyst volume wasIOpercent of the total yolume of catalyst'au'd'reactants; The alkylationwas a batch reaction,"- and the purified product-had-a boiling range of624m 660 F. (atmospheric pressure) and a specific gravity at 1 5 m s rosqfiwmaasfllp i w added t 18 moles of th urijed dixylylbutane, .togetherwith app iliirj iately grams of zinc dust, employing 300 cc. 1 Zane ;diljient. Previous experiments showed that i t i e w h ben n and ul m mchloride piesericeof zinc, below a temperature of 70 f t n a mixture.was ,warnied ,to 45 thus start iigt U cho and waslhen cooled to v to C.whe'fEmiSstof the ieactioh was permitted to take t place. Toward -theend .of the reaction {the temperature was "dlto'ffl 1C1 hereacti oriadmixture contained an s'iof sulfur ;morioch l6ride, a major proportionof j'liilil was segmgted rram' sulfurized 'lpro'du ct, ,togetli r. W;hQthe Ibeniene' diluent byfvac'uum distillation,

ssesfor the remoyal of elementary sulfur from its adfixture with asulfurized'hyd'ocarbon compound emplayin Silitii gelf llpoii washingwithfli) percent benzene in pentane, the sulfurized dixylylbutane wasobtained .ttea t ast iame lhi tmateat ailatesim zi hst lstea was boiledwith barium oxide for three hours. was added to distill out the.residual toluene and then the xylene was distilled. The product wasstripped with gas found upon analysis to c o ntai n 12:03 weight percentsulfur, 0.10 weight percent ash and 1.37 weight percent chlorine, andwas tested asdescribed in Example 3.

Toluene was introduced into an allgylatign zone,;,with 1,3-butadiene ina mol ratio to butadi ne of approximately' 10:1 (2565 pounds of :totalreactants and alkylated with the butadiene at atmospheric pressure andat a H2O catalyst, to form ditolylbutane. The catalyst was prepared bymaking a saturated solution of BFa in water. Th

i its l it t -p tas t s i h u 30 msof i .dus't, asainengp oy n b zen adiluent." Iii ereactiontemperatureiwas.maintained th 5 C for aboiitone'hour. Thetemperature towardthe he eacti oji l ;.was raised .to7.0IC. Thefreactiop awed xq i v it 6fi f9 l9fi,

p rated from the sulfurized prod i t at unh fiulfurind PRQ JP Example 3q i nqit --i Base- Lubricating Oil, Weight Percent 100.0 99. 5

Sulfurized dixylylbntane, W t'Perpent 0.0 0.5 sulfurized ditolylbu e, Wght 'Percent .-Purifiedtproduet.of,Example 1.

fli a flt srqqe tQFEWPW- .hc e..compo i. ions were evaluated. in.-m9untcd-sing1e ylin er ;H 2 La son t st engine. Thetc psrf rmedconsisted inrplacing BOOgrams of the composition in the Xylene rt.iLofwhiizh, together .withdhhenzgge a crankcaseofthe singlet cylinderLauson 1(gaso1ine).engine,

The bearing weight loss, in milligrams, encountered in each test was asfollows:

It will be seen from these data that the addition of a relatively smallproportion of an improvement agent of our invention, to a typicalcrankcase lubricant, decreases the bearing weight loss to a satisfactorylow value.

While the invention has been described in connection with a present,preferred embodiment thereof, it is to be understood that thisdescription is illustrative only and is not intended to limit theinvention.

We claim:

1. As a new composition, a mineral lubricating oil containing an amountsuflicient to impart antioorrosion properties thereto, of a product ofsulfurization of a diarylalkane containing from 4 to 12 alkane carbonatoms obtained when employing sulfur monochloride as the sulfurizingagent.

2. A lubricating oil composition comprising a mineral oil having aviscosity index of at least 50 and containing an amount suflicient toimpart anticorrosion properties thereto, of a product of sulfurizationof a diarylalkane containing from 4 to 12 alkane carbon atoms, obtainedwhen employing sulfur monochloride as the sulfurizing agent.

3. The composition of claim 2 wherein said diarylalkane is a diphenylalkane.

4. The composition of claim 3 wherein said diphenylalkane isdixlylbutane.

5'. The composition of claim 3 wherein said diphenylalkane isditolylbutane.

6. A lubricating oil composition comprising a mineral lubricating oilcontaining from 0.1 to percent by weight, based on said composition, ofa product of sulfurization of a diarylalkane containing from 4 to 12alkane carbon atoms obtained when employing sulfur monochloride as thesulfurizing agent.

7. The composition of claim 6 containing from 0.1 to 3 weight percent ofsaid sulfurized diarylbutane.

8. A lubricating oil composition comprising a mineral lubricating oilcontaining from 0.1 to 10 weight percent of a product of sulfurizationof diphenylbutane obtained when employing sulfur monochloride as thesulfurization agent.

9. A lubricating oil composition comprising a mineral lubricating oilcontaining from 0.1 to 10 Weight percent of a product of sulfurizationof ditolylbutane obtained when employing sulfur monochloride as thesulfurization agent.

10. As a new composition, a mineral lubricating oil containing an amountsufiicient to impart anticorrosion properties thereto, of a product ofsulfurization of a diarylalkane containing from 4 to 12 alkane carbonatoms obtained when employing sulfur monochloi'ide as the sulfurizingagent.

11. As a new composition, a mineral lubricating oil containing an:amount sutficient to impart anticorrosion properties thereto of aproduct of sulfurization of a diarylalkane, obtained when employingsulfur monochloride as the sulfurizing agent, said 'diarylalkane havingbeen prepared by the alkylation of an aromatic hydrocarbon With aconjugated diolefin hydrocarbon containing from 4 to 12 carbon atoms inthe molecule, and said sulfurization having been conducted at atemperature in the range of 20-110 C.

12. The composition of claim 11 wherein said diolefin hydrocarbonreactant contains from 4 to 6 carbon atoms in the molecule.

13. A composition of claim 12 wherein said diolefin is 1,3-butadiene andsaid aromatic hydrocarbon is xylene.

14. A composition of claim 12 wherein said diolefin is 1,3-butadiene andsaid aromatic hydrocarbon is toluene.

15. As a new composition, a mineral lubricating oil containing an amountsufficient to impart anticorrosion properties thereto of a product ofsulfurization of a diarylalkane, obtained when employing sulfurmonochloride as the sulfurizing agent, said 'diarylalkane having beenprepared by the alkylation of an aromatic hydrocarbon with a conjugateddiolefin hydrocarbon containing from 4 to 12 carbon atoms in themolecule, and said sulfurization having been conducted at a temperaturein the range of 20-110 C. with sulfur monochloride having beenintroduced into the sulfurization zone in a mol ratio to saiddiarylalkane therein in the range of from about 0.5 :1 to 2:1, and for aperiod of from 30 to minutes. 7

16. A composition of claim 15 wherein said aromatic hydrocarbon isselected from the group consisting of benzene, naphthalene, anthracene,phenanthrene, toluene, xylene, phenol, dimethyl naphthalene, diamylnaphthalene, 'dioctyl naphthalene, di-tert-butyl anthracene, di-isoamylphenanthrene, tri-tert-butyl phenanthrene, methyl-tertbutyl naphthalene,ethyldodecyl benzene and cumene, and wherein said diolefin is selectedfrom the group consisting of 1,3-butadiene, 1,3-pentadiene,1,3-hexadiene, 2methyl- 1,3-pentadiene, 1,3-dodecadiene,2,4-dodecadiene, 3,5- dodecadiene, 4,6-dodecadiene, 5,7-dodecadiene,conjugated heptadiene and conjugated octadiene.

17. A composition of claim 15 wherein said sulfurization is eflfected inpresence of zinc as a catalyst.

18. A composition of claim 2 wherein said diarylalkane contains saidaryl groups attached to alkane carbon atoms, which atoms are separatedby no more than one carbon atom.

References Cited in the file of this patent UNITED STATES PATENTS2,176,632 Magill Oct. 17, 1939 2,244,886 Lincoln et al. June 10, 19412,253,228 Cantrell et al. Aug. 19, 1941 2,380,072 Reid July 10, 19452,429,691 Johnson et 'al. Oct. 28, 1947 2,439,228 Sturrock et al. Apr.6, 1948 2,497,138 Rogers Feb. 14, 1950

2. A LUBRICATING OIL COMPOSITION COMPRISING A MINERAL OIL HAVING AVISCOSITY INDEX OF AT LEAST 50 AND CONTAINING AN AMOUNT SUFFICIENT TOIMPART ANTICORROSION PROPERTIES THERETO, OF A PRODUCT OF SULFURIZATIONOF A DIARYLALKANE CONTAINING FROM 4 TO 12 ALKANE CARBON ATOMS, OBTAINEDWHEN EMPLOYING SULFUR MONOCHLORIDE AS THE SULFURIZING AGENT.